Chap. VII. POLYGAMOUS PLANTS. 293 



reduction of the pistil in the male and hermaphrodite 

 flowers of our Euonymus ; though this view does not 

 account for the pistils in the poUeniferous flowers 

 being sometimes longer than those in the female 

 flowers. 



Fragaria vesoa, Virginiana, Chiloensis, &c. (Rosacese). 

 — A tendency to the separation of the sexes in the 

 cultivated strawberry seems to be much more strongly 

 marked in the United States than in Europe ; and 

 this appears to be the result of the direct action of 

 climate on the reproductive organs. In the best ac- 

 count which I have seen,* it is stated that many of the 

 varieties in the United States consist of three forms, 

 namely, females, which produce a heavy crop of fruit, — 

 of hermaphrodites, which " seldom produce other than 

 a very scanty crop of inferior and imperfect berries," 

 — and of males, which produce none. The most skilful 

 cultivators plant " seven rows of female plants, then 

 one row of hermaphrodites, and so on throughout the 

 field." The males bear large, the hermaphrodites 

 mid-sized, and the females small flowers. The latter 

 plants produce few runners, whilst the two other forms 

 produce many; consequently, as has been observed 

 both in England and in the United States, the poUeni- 

 ferous forms increase rapidly and tend to supplant 

 the females. We may therefore infer that much more 

 vital force is expended in the production of ovules 

 and fruit than in the production of pollen. Another 

 species, the Hautbois strawberry {F. elatior), is more 

 strictly dioecious ; but Lindley made by selection an 

 hermaphrodite stock.f 



Bhamnus oathariieus (Rhamneas). — This plant is well 



* Jfr. Leonard Wray in ' Gard. infovmation on this subjeot, sea 

 Chron.' 1861, p. 716. 'Variatiim under Domestication,' 



t For rei'erencoa and I'urther chnp. i.. 2ud edit. vol. i. p. 375. 



